Adalbert kolb



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ADALIBERT KOLB, 0F CHARLOTTENIBURG-WESTEND, GERMANY, assrenon TO HErnnmn'rrr COMPANY, on NEW YORK, n. Y.

PROCESS OF PRODUCING GHBOMIUM-CONTAINING SILICATES. I

1,193,794. No Drawing.

To all whom it may concern:

Be it known that I, ADALBERT KOLB, proat No. 6 Leistikowstrasse,Charlottenburg- Westend, near Berlin, German Empire, have invented newand useful Improvementsin Processes of Producing Chromium-ContainingSilicates; and I do hereby declare the following to be a full, clear,and exact de- In technical literature it is stated that base exchangingchromium-containing silicates cannot be produced (compare Gmelin= Kraut:Text Book of Inorganic Ukemistry, 7 edition, Volume III 1, page 1314, orF. Singer: On Artificial Zeolites, Dissertation at the TechnicalUniversity, Berlin, 1910, ex-

periment 27, pages 3637 and page 45.) Further it is said that by meltingtogether suitable quantities of sodium oxid, chromium oxid,'silicicacid, a' glass like product is obtained, which, when lixiviated withwater, forms a slime, which has not a base exchanging property (seeGmelin-Kraut, same volume, page 1392, or Singers Dissertation, page 36).According to these authorities there is no possibility of obtaining baseexchanging silicates containing chromium, and from a theoreticalstandpoint there is no reason to take the opposite view, because in thechromites the alkali is butloosely united and chromium does not form asimple compound with silicic acid (see Gmelin-Kraut above).

Now it has been found that, contrary to previous experience, baseexchanging silicates containing chromium can be obtained, and indeedfrom alkaline chromite salt solutions, by adding alkali silicate. Indoing so it is necessary to avoid a considerable excess of free alkali,not to dilute the solutions too much, and to work without heating thesame. In order to convert the precipitate into a granular, hard andsolid form suitable for technical purposes, said precipitate, whendecanted, is washed (a small residue of free alkali being purposely lefttherein) then pressed, dried and the hard material or press cakeobtained is introduced into hot water. The hot mass breaks up with aloud crackling sound into green, or dark green,

coarsely granular, crystal pieces which cons1st of sodium oxld, chromiumoxid, silicic Specification of Letters Patent.

' Patented Aug. 8, 1916.

acid and water, and, in addition to their base exchanging property, arecharacterized by hardness and high resistance to hot water and coldacids.

According to the described process it is possible to obtain not onlysilicates containing chromium, but also other analogous-compositionshaving like properties, if, instead of chromium 'salts, or in lieu of orin addition thereto, there are used solutions of other alkali solubleoxide of more or less' acid properties, such as the oxids or boron,vanadium, tungsten, etc. Further, it has been found that the saltsolutions in question need not be pure, but that mixtures of chromitesilicates and the like containing these or other base exchanging bodiessuch as alumina, in greater or less proportion can also be produced, andthat the mixed products obtained also have a high resistance tomechanical strains and chemical reagents. Such mixed exchange silicatesare produced by precipitating mixtures of chromium solutions, etc., withaluminate solutions, etc., by means of corresponding quantities ofsilicate'solutions and by drying the deposits obtained and treating thesame with hot water. Instead of previousl making the alkaline solutionsof these su stances, mixtures of non-alkaline chromium salt solu tions,etc., with solutions of other suitable salts, for example aluminium,zinc, lead, etc., salts can be precipitated by the requisite amount ofsilicate solution containing suflicient alkali to neutralize the acid ofsuch salt solutions.

In a typical embodiment of my process 38 parts by weight, as forexample, 38 kilograms, of chrome potash alum (or correspondingquantities of chromium sulfate or otherchromium salts) are dissolved in200 liters of water and the solution is shaken and introduced into 33liters of technical soda lye of 395 Baum diluted with the same volume ofWater, that is into the quan-- posit formed is washed, pressed and driedata temperature below 100 C. As a consequence a dark green, granularmass is obtained, which, when washed with hot water, decomposes andforms a hard, uniformly coarse, granular product.

In another embodiment, 19 kilograms of chrome alum (or a correspondingquantity of other chromium salts) and 12.5 kilograms aluminium sulfateare dissolved in 150 ln'lograms of water, and the solution is introducedinto such a quantity of soda lye that the hydroxids first precipitatedare again dissolved, and the solution still remains clear when diluted.The mixture is then brought to about 500 liters by adding water, andwhile stirring same it is mixed with the corresponding quantity ofdiluted water glass solution (about 30 kilograms of 39 Baum solution).After stirring the same for some time the precipitate is washed, driedand treated with hot water.

In still another embodiment, 19 kilograms of chrome alum (or acorresponding amount of other chromium salts) and 14.5 kilograms of zincsulfate are dissolved in 500-750 liters of water, and the solution isthen mixed with a mixture of 36 kilograms of water glass solution (ofabout 39 Baum), 50 1iters of soda lye (40 Baum) and 50liters of waterand well stirred. The precipitate obtained is then treated as above setforth.

The base exchanging chromite silicates or other analogous metalsilicates of high chemical resistance can be used in the same manner asexchange silicates or artificial zeolites, for purifying water, forremoving undesirable salts from solutions, for producing new salts bybase exchange, etc., but they are superior to the alumina-containingsilicates heretofore used for the same purpose owing to their greathardness and corporated catalytically acting metal oxids by treatmentwith metal salt solutions, in which case materials are obtained, whichare particularly suitable for carrying out cata--' lytic processes ofall kinds and especially for carrying out oxidations in aqueous solu-'tions.

What I claim and desire to secure by Let- 'ters Patent of the UnitedStates is 1. The process of producing exchange silicates which comprisesprecipitating a so lution containing chromium with an alkaline solutioncontaining dissolved silica and washing and drying the precipitate.

2. The process of producing exchange silicates which comprisesprecipitating an alkaline solution containing chromium with an alkalinesolution containing dissolved silica and washing and drying theprecipitate.

3. The process of producing exchange silicates which comprisesprecipitating a solution containing chromium with an alkaline solutioncontaining dissolved silica and washing, pressing and drying theprecipitate.

4. The process of producing exchange silicates which comprisesprecipitating an alkaline solution containing chromium with an alkalinesolution containing dissolved silica and washing, pressing and dryingthe pre-

